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  • Writer's pictureSarah Lozanova

Floatovoltaics: What To Know About Floating Solar Panel Farms

Updated: Nov 12

Solar panels floating on water in a pond.

If the use of solar energy is to increase dramatically, many rooftops and plots of land need to be covered in photovoltaic (PV) modules. Roofs are often excellent for solar panels, but not all are well-suited for panels, and vacant land is often scarce and expensive in urban areas. Another idea is to use the vast area of the Earth covered in water to generate solar power.

Thus, a newer alternative, floating photovoltaic systems, is gaining popularity for certain applications. But are floating solar panels the new frontier of clean energy or too expensive and impractical? Let’s explore this innovative topic to find out.

What Is Floating Solar?

Floatovoltaics or floating photovoltaics (FPV) projects have solar modules that float on a body of water, including lakes, lagoons, ponds, reservoirs, and rivers. The PV panels need to be above the surface of the water, so they are usually attached to something buoyant that doesn’t rust easily. Floating solar farms are gradually becoming more widespread, especially near densely populated areas where vacant land is scarce or prohibitively expensive.

Some of the most common placements of floating solar farms currently include hydroelectric dam reservoirs, drinking water reservoirs, and wastewater treatment ponds. These manufactured bodies of water are already disturbed sites, and hydropower plants have existing power transmission infrastructure for distributing the hydropower.

However, some solar developers are also experimenting with mounting solar panels out at sea on offshore solar farms. Oceans cover 70% of the surface of our planet, so there is ample space for mounting PV panels. However, installing solar panels at sea can present additional challenges.

Potential Benefits Of Floating Solar Panels

Locating utility-scale renewable energy projects near population centers is ideal, but available land is relatively scarce and expensive in most urban areas. In rural farming communities, where land is more plentiful, there is concern that converting farmland to utility-scale solar farms could be detrimental to food security. However, floating solar photovoltaics take up little or no land area and take advantage of space that has few, if any, other development opportunities.

Solar panel efficiency often decreases when they heat up above 77°F. For example, most solar panels have a temperature coefficient of -0.3%°C to -0.5%°C. That means that for every degree Celsius, the efficiency reduces by a fraction of a percent. Unfortunately, in hot climates, this reduction in efficiency can really reduce solar power output. Mounting solar PV panels above water can have a natural cooling effect, boosting solar energy production.

Another benefit of floatovoltaics is that modules can help shade the body of water, preventing freshwater evaporation. This can be especially beneficial in dry climates or during droughts. In fact, a 2021 study showed that covering 4,000 miles of California canal with solar canopies could conserve 65 billion gallons of water annually by reducing evaporation.

When solar contractors install floating solar farms at hydroelectric dam reservoirs, they can often use the existing utility infrastructure for the solar energy, reducing development costs. Likewise, solar engineers are also examining combining offshore wind farms and floating solar farms, which can use the same transmission line. For example, there is a project planned in the North Sea near the Netherlands with 5 megawatts of solar capacity, aiming to begin operation in 2026.

Current Roadblocks For Offshore And Floating Solar

Although there are many benefits to floating solar farms, there are some disadvantages to overcome. Typically, there are more challenges with floating solar installations located in salt water because salt water it can leave a film on the modules, decreasing solar energy output. This can also be an issue for land-based projects near the ocean that receive salt spray.

Because floating solar farms are less common, they require special equipment that keeps the modules above the surface of the water. This is more sophisticated and complex than standard roof or ground-mounted racking systems. Also, because this is a niche market, these materials can be more expensive, driving up costs.

These solar projects are also more complex from an engineering standpoint due to potential wind speeds, corrosion, anchoring complications, and water movement. Site selection can be difficult and time-consuming, increasing permitting issues and development and construction costs.

Also, constructing floating solar power plants can damage the environment and disrupt aquatic life, especially in pristine areas. Once installed, the modules shading the water's surface reduce available sunlight, altering ecosystems. For example, research has shown that floating solar farms can impact the stratification in a water body. Changes in water stratification can cause the lower layers to become deoxygenated, increasing nutrient concentrations and killing fish. More research is needed to learn about the ecological implications of floating solar.

What Offshore Solar Projects Exist Today?

Numerous countries are constructing utility-scale floating solar farms, including China, India, Taiwan, South Korea, Germany, the Netherlands, and the United States. Although some are operational, many are in various stages of development.

The largest operational floating project is Dingzhuang solar farm in eastern China. This 320-megawatt project is mounted on a reservoir, is connected to a 100-megawatt wind farm, and has 8-megawatt hours of battery storage.

By contrast, the largest floating solar farm online in the United States, the Healdsburg project in California, is much smaller. This 4.8-megawatt project is located on 15 acres of ponds at a wastewater treatment plant.

The largest planned FPV project is the Saemangeum floating solar farm in South Korea. This 2.1-gigawatt project aims to be operational in 2030 and can help the country significantly reduce its dependence on fossil fuels. It will be located in tidal flats on the Yellow Sea coast, co-located with an onshore solar farm.

In India, a 600-megawatt FPV plant is under construction near the Omkareshwar Dam on the Narmada River. The largest floating solar park in Europe under construction is in Portugal at the Alqueva Reservoir. This 5-megawatt project will accompany a hydroelectric dam and produce electricity that is more cost-effective than power from natural gas power plants.

Taiwan has become a leader in ocean-based offshore solar farms because space on land is at a premium on the island, yet there is plenty of space at sea. In recent years Chenya Energy completed a 180 MW project off the west coast of Taiwan and is planning more offshore solar projects.

SolarDuck, a Dutch-Norwegian floating solar developer, will develop a 500-kilowatt offshore pilot project in the North Sea consisting of six interconnected platforms on synthetic anchors at an offshore wind farm.

How Much Might Floating Solar Cost?

The cost of floating solar farms varies depending on numerous factors, including the cost of anchoring systems, transmission infrastructure, real estate leases, labor, and system capacity. For example, the Saemangeum project is estimated to cost $3.82 billion, and the smaller solar farm on the Narmada River has a price tag of $4.1 million.

Some more experimental projects, such as the Dutch project in the North Sea, are still in the pilot phase. Thus, the cost per MW is much higher because they are smaller in scale and require more research.

Floating Solar Panels: Solar Installations Of The Future?

Although floatovoltaic projects are promising in certain areas, they are not ideal for all locations. This application is most appealing in areas where land is scarce and existing transmission infrastructure is in place. Often, the most attractive sites are reservoirs at hydroelectric dams, but some solar developers are examining ocean-based applications at offshore wind farms and tidal flats.

Although many floating projects have been completed, more research is needed to advance this approach. For example, research is needed to understand the ecological impacts of floating solar farms or the best way to anchor them.

Are you working on a challenging solar project? Partner with GreenLancer for your next photovoltaic installation!

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